I live in Connecticut, but I was imagining this would be a Fraser v. Bethel question. One of my friends was wearing this hoodie: [link removed]. The teacher didn't know what it stood for, but because nobody wanted to tell him he assumed it was inappropriate. Tiny Meat Gang is a YouTube musical group, but "tiny meat," of course, refers to a small penis.
The teacher assumed correctly: it is inappropriate.
Refer to the school's dress code. My district has the following clause in its dress code: A student's dress shall
not include items that are vulgar, obscene, discriminatory, libelous or denigrate others based on a person’s actual or perceived race, color, weight, national origin, ethnic group, religion, religious practice, gender, sexual orientation, sex or disability. The bolding is mine, for emphasis. Any references to genitalia is pretty much vulgar, even if it just happens to be a musical group's name.
Like, the group choose their name, not knowing the meaning of the phrase? Puhleez! We're old, not stupid.
This is not a free speech issue, and given that the Supreme Court ruling takes precedence over any lower court's ruling on the subject, it is odd that you reference Fraser v. Bethel: the majority opinion was in favor of the school district.